Highly sensitive toluene sensor based on silver Ear-Like F-doped Co3O4 templated from Co(OH)F Guided by SiO2 nanospheres

This study successfully synthesized “silver ear-like” Co(OH)F using 15 nm SiO 2 spheres as seeds. Gas sensitivity of Co(OH)F with and without SiO 2 spheres to toluene was compared at different annealing temperatures. The results demonstrate that the Co(OH)F-Si-350 sensor exhibits optimal gas sensitivity to toluene, with a response of 35 (R g /R a ) to 100 ppm of toluene at 220℃, with response and recovery times of 50 s and 80 s, respectively. Notably, the sensor detected toluene concentrations as low as 50 ppb, indicating good sensitivity to low concentrations. These findings suggest that the structural transformation resulting from the introduction of SiO 2 nanospheres, forming ultra-thin nanosheet clusters (∼12 nm), provides abundant active sites, effectively promoting substance diffusion and adsorption/desorption processes. Additionally, the incorporation of fluorine enhances the Lewis acidity of the material, facilitating the formation of stable adsorption states for gas molecules on the surface. These results reveal the significant impact of the structural transformation caused by the introduction of SiO 2 nanospheres on gas sensitivity, providing a strong theoretical foundation for further optimizing gas sensor design.